Japanese Patent Laid-Open No. 2000-299400 (Patent Document 1) discloses a technology, in a non-leaded flat package, of removing a sealing material present between leads by using a punching die and covering exposed leads with a metal film by plating for enhancing their solder adhesion, in order to prevent a short-circuit between leads at the time of packaging.
Japanese Patent Laid-Open No. Hei 4-157761 (Patent Document 2) discloses a technique, in resin sealing with a lead frame, of using laser irradiation for removing a resin piece formed at a resin dam portion.